This invention relates to a picture control device for a flat-panel display represented by a liquid-crystal display, and a flat-panel display device having the picture control device.
Recently, flat-panel displays, particularly liquid-crystal displays, have become popular as displays for use with personal computers, word processors, and TV displays, because of the advantages of lightweight, thinness, and low power consumption.
A conventional liquid crystal display has, for example, eight X-TCPs (Tape Carrier Packages) 701, 702, 703, 704, 705, 706, 707, 708 arranged along one side edge 101 of a liquid crystal panel 100 as shown in FIG. 1. Each X-TCP is a unit formed of a flexible wiring film and a driver IC which is mounted on the flexible wiring film in the form of a semiconductor chip, and supplies picture signal voltages to signal lines of the liquid crystal panel 100. Although not shown, a plurality of Y-TCPs are arranged along another side edge of the liquid crystal panel 100 to output a scanning pulse to the scanning lines in sequence. Each Y-TCP is a unit formed of a flexible wiring film and a driver IC which is mounted on the flexible wiring film in the form of a semiconductor chip.
The X-TCPs 701, 702, - - - , 708 are connected in cascade, and to a control section G/A in a drive circuit board. The control section G/A generates a horizontal clock signal CK and horizontal start signal ST in synchronism with a system clock signal SCK supplied externally, and also generates pixel data D (R), D (G), D (B) of red (R), green (G), and blue (B) according to video data DATA to be supplied to the X-TCPs 701, 702, - - - , 708 as control signals. The horizontal clock signal CK and the pixel data D (R), D (G), D (B) are commonly supplied to the X-TCPs 701, 702, - - - , 708. The horizontal start signal ST is supplied to the first X-TCP 701, and then transferred sequentially through the X-TCPs 701, 702, - - - , 708. Each of the X-TCP 701, 702, - - - , 708 is constituted by a shift register which outputs the horizontal start signal ST in response to the horizontal clock signal CK while shifting the horizontal start signal ST to the next stage, and a D/A converter which samples the pixel data at the output timing of each horizontal start signal ST, converts the pixel data into a picture signal voltage, and supplies the pixel signal voltage to a signal line corresponding to the stage of outputting the horizontal start signal ST.
Recently, reduction of power consumed by the flat-panel display is strongly demanded. According to a technique conventionally known, power consumption of the flat-panel display is reduced by forcing the D/A converter of each X-TCP to be suspended except for a period of driving a corresponding signal line. However, the demand is not sufficiently satisfied by the technique.
It is, accordingly, an object of the present invention to overcome the disadvantage in the prior art by providing a flat-panel display that fulfills the demand for reduced power consumption.
The foregoing object is accomplished by a picture control device for a flat-panel display device having a plurality of horizontal pixel lines each formed of display pixels arranged in one line, comprising a plurality of driving sections arranged to divide the display pixels into groups, for driving the groups of display pixels, respectively; and a control section for controlling the driving sections to output pixel data assigned to the respective display pixels during a scanning period for each horizontal pixel line and to drive the display pixels according to the pixel data; wherein the control section includes a plurality of data wiring members electrically separated from each other and a data distributing circuit connected to the driving sections by the respective data wiring members, for distributing pixel data assigned to the display pixels of each group to a corresponding driving section via a corresponding data wiring member.
With the picture control device, the control section is constituted by a plurality of data wiring members and a distributing circuit. The data wiring members are electrically separated from each other. The data distributing circuit is connected to the driving sections by the respective data wiring members, and distributes pixel data assigned to the display pixels of each group, to a corresponding driving section via a corresponding data wiring member. Since the wiring length of each data wiring member is shortened to half of the wiring length of a conventional data wiring member which supplies pixel data commonly to all the driving sections, the parasitic capacitance of the control section can be greatly reduced. Accordingly, it is possible to sufficiently reduce the power consumption of the control section while increasing the operation speed of the control section.